diff options
Diffstat (limited to 'net/mac80211/tx.c')
| -rw-r--r-- | net/mac80211/tx.c | 93 |
1 files changed, 63 insertions, 30 deletions
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 680bcb7093db..698d4718b1a4 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1092,6 +1092,59 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx, return true; } +static bool ieee80211_tx_prep_agg(struct ieee80211_tx_data *tx, + struct sk_buff *skb, + struct ieee80211_tx_info *info, + struct tid_ampdu_tx *tid_tx, + int tid) +{ + bool queued = false; + + if (test_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state)) { + info->flags |= IEEE80211_TX_CTL_AMPDU; + } else if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) { + /* + * nothing -- this aggregation session is being started + * but that might still fail with the driver + */ + } else { + spin_lock(&tx->sta->lock); + /* + * Need to re-check now, because we may get here + * + * 1) in the window during which the setup is actually + * already done, but not marked yet because not all + * packets are spliced over to the driver pending + * queue yet -- if this happened we acquire the lock + * either before or after the splice happens, but + * need to recheck which of these cases happened. + * + * 2) during session teardown, if the OPERATIONAL bit + * was cleared due to the teardown but the pointer + * hasn't been assigned NULL yet (or we loaded it + * before it was assigned) -- in this case it may + * now be NULL which means we should just let the + * packet pass through because splicing the frames + * back is already done. + */ + tid_tx = tx->sta->ampdu_mlme.tid_tx[tid]; + + if (!tid_tx) { + /* do nothing, let packet pass through */ + } else if (test_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state)) { + info->flags |= IEEE80211_TX_CTL_AMPDU; + } else { + queued = true; + info->control.vif = &tx->sdata->vif; + info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING; + __skb_queue_tail(&tid_tx->pending, skb); + } + spin_unlock(&tx->sta->lock); + } + + return queued; +} + /* * initialises @tx */ @@ -1104,8 +1157,7 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata, struct ieee80211_hdr *hdr; struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); int hdrlen, tid; - u8 *qc, *state; - bool queued = false; + u8 *qc; memset(tx, 0, sizeof(*tx)); tx->skb = skb; @@ -1157,35 +1209,16 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata, qc = ieee80211_get_qos_ctl(hdr); tid = *qc & IEEE80211_QOS_CTL_TID_MASK; - spin_lock(&tx->sta->lock); - /* - * XXX: This spinlock could be fairly expensive, but see the - * comment in agg-tx.c:ieee80211_agg_tx_operational(). - * One way to solve this would be to do something RCU-like - * for managing the tid_tx struct and using atomic bitops - * for the actual state -- by introducing an actual - * 'operational' bit that would be possible. It would - * require changing ieee80211_agg_tx_operational() to - * set that bit, and changing the way tid_tx is managed - * everywhere, including races between that bit and - * tid_tx going away (tid_tx being added can be easily - * committed to memory before the 'operational' bit). - */ - tid_tx = tx->sta->ampdu_mlme.tid_tx[tid]; - state = &tx->sta->ampdu_mlme.tid_state_tx[tid]; - if (*state == HT_AGG_STATE_OPERATIONAL) { - info->flags |= IEEE80211_TX_CTL_AMPDU; - } else if (*state != HT_AGG_STATE_IDLE) { - /* in progress */ - queued = true; - info->control.vif = &sdata->vif; - info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING; - __skb_queue_tail(&tid_tx->pending, skb); - } - spin_unlock(&tx->sta->lock); + tid_tx = rcu_dereference(tx->sta->ampdu_mlme.tid_tx[tid]); + if (tid_tx) { + bool queued; - if (unlikely(queued)) - return TX_QUEUED; + queued = ieee80211_tx_prep_agg(tx, skb, info, + tid_tx, tid); + + if (unlikely(queued)) + return TX_QUEUED; + } } if (is_multicast_ether_addr(hdr->addr1)) { |